Summary: This paper exploits the staggered rollout of Thailands universal health coverage scheme to estimate its impacts on whether individuals report themselves as being too ill to work. The statistical power comes from the fact that there is an average of 62,000 respondents in the labor force survey at each survey date and no less than 68 survey dates, most of which are just one month apart. The analysis finds that universal coverage reduced the likelihood of people reporting themselves to be too sick to work: the authors estimate the effect to be -0.004 one year after universal coverage and -0.007 three years after. The estimated effects are much larger among those age 65 and over. Universal coverage had a much larger effect on health (about four times larger) than the Village Fund scheme, which provided free credit to rural households through a subsidized microcredit scheme and which was rolled out around the same time as universal coverage.